Treatment of solid carbon containing materials to produce carbon monoxide for the synthesis of organic materials



July 8, 1952 N. l.. D|cK|NsoN 2,602,809

TREATMENT OF' SOLID CARBONCONTAINING MATERIALS TO PRODUCE CARBON MONOXIDE FOR THE SYNTHESIS OF ORGANIC MATERIALS ATTENE'YS July 8, 1952 N. 1 DlcKlNsoN 2,602,809

TREATMENT OF SOLID CARBON CONTAINING MATERIALS TO PRODUCE CARBON MONOXIDE FOR THE SYNTHESIS OF ORGANIC MATERIALS Filed July lO, 1948 5 Sheets-Sheet 2 I N VEN TOR.

N o m, m WWW July 8, 1952 N. DlcKlNsoN TREATMENT OF SOLID CARBON CONTAINING MATERIALS TO PRODUCE CARBON MONOXIDE FOR THE SYNTHESIS OF ORGANIC MATERIALS 3 Sheets-Sheet 5 Filed July l0, 1948 Patented July 8, 1952 TREATMENT OF SOLID CARBON CONTAIN- ING- MATERIALS T PRODUCE CARBON MONOXIDE FOR THE SYNTHESIS 0F 0R- GANIC MATERIALS Norman L. Dickinson, Basking Ridge, N. J., as-

signor to The M. W. Kellogg Company, Jersey City, N. J., a corporation of Delaware Application Iluly 10, 1948, Serial No. 38,134

l This invention relates to the treatment of carbon-containing materials. In one aspect this 18 Claims. (Cl. 2260-449) invention relates to the treatment of solid carbon-containing materials, such as coal and coke, to produce oxides of carbon therefrom. In still another aspect this invention relates to an integrated process for the production of organic compounds having more than one carbon atom per molecule from solid carbon-containing materials.

Coal and coke may be treated with oxygen and/or steam at relatively` high temperatures to convert the coal or coke to hydrogen and carbon monoxide, which products are useful for various purposes including the synthesis of organic compounds therefrom. When steam is used alone to gasify coal or coke it is necessary to supply heat from an external source, which factor makes such a process using steam alone expensive and ineiiicient. The use of oxygen alone is also uneconomical for obvious reasons and the heat released by gasifying coal with relatively pure oxygen tends to be excessive. AS the result, steam and oxygen are normally used together in such proportions that the net reaction heat is sumcient to maintain the desired temperatures ior the gasification of the coal or coke. In using the combination of steam and oxygen in the above manner the oxygen may be used in a substantially pure form and by such method the process is continuous, thermally efficient, and produces a gas comprising hydrogen and carbon monoxide. Even with the combination of steam and oxygen the purification of the oxygen often prevents such processes from being economically sound. If the oxygen is to be supplied to the process as air rather than as purified oxygen, the economical advantages obtained by using air is obviated by the fact the product gas contains large amounts of diluent nitrogen. It is desirable, therefore, to provide a process which eliminates puriiication of the oxygen Ibut produces a gas substantially free `from nitrogen.

The object of this invention is to provide a process for gasifying solid carbon-containing materials.

It is another object of this invention to con- Still another object of this inventionV is lto provide a process for the reduction of metal oxides.

It is a further object of this invention to provide an integrated process for the gasification n of coal and coke, such as coke breeze, which cannot be processed economically in present processes by virtue of their small particle size;

Various other objects and advantages will become apparent to those skilled in the art from the' accompanying description and disclosure.

According to this invention solid carbon-containing materials are oxidized to convert them to carbon oxides by indirect oxidation with air in a manner such that the nitrogen of the air does not contaminate the product gas. The gasification of the carbon-containing materials is accomplished by the alternate oxidation and reduction of a fluidized metal oxide. According to this invention, ysolid fuels are converted tor gases by contacting a metal oxide with iinely-` divided solid carbon-containing materials under conditions such that the metal oxide is reduced and the 4carbon of the solid fuel is oxidized to carbon oxides, the metal oxide being the principal source oi oxygen for the oxidation of carbcn. After the reduction of the metal oxide, the reduced metal oxide is reoxidized and the cycle I repeated. The metal oxide may be reduced during gasiiication or" the coal or coke to the elelmentary metal or to a lower oxide, as desired.

As used herein,.reduced metal oxide refers to either elementary metal or a lower metal oxide resulting from the reduction of the metal oxide.

According to the preferred embodiment of the present invention, gasification of the solidjcar bon-containing material, such as coal or coke, and the reduction of the metal oxide are effected in a reaction Vzone containing a mass of fluid-v ized metal oxide, such as magnetite (FesOr) or` hematite (FezOs), maintained at an appropriate temperature of gasification into which iinelydivided coal or `coke is introduced. The metal oxide and solid carbon-containing material are maintained in ,al fluidized condition with a gasiform fluid substantially free from free oxygen. A gaseous efliuent rich in carbon oxide is withdrawn from the reaction zone; at the preferred operating conditions the carbon oxide is carbon monoxide. Upon reduction of metal oxide to the extent desired or economical, reduced metal oxide is Withdrawn and contacted with an oxidizing gas, such as air or steam, under conditions such that the reduced metal oxide is re.- oxidized. Reoxidized metal oxide is returned to the gasification zone. A

When it is desired to produce hydrogen in order to blend with the carbon oxide, such asY carbon monoxide, to produce a gas suitable for 'the synthesis of organic compounds, a portion of thereduced metal oxide in a fluidized condition is contacted with steam at an elevated temperature under conditions such that the reduced metal oxide is reoxidized and hydrogen is produced. The hydrogen thus produced may be blended with the carbon monoxide produced in the gasification or reduction step or may be used separately. The gasification of coal with a metal oxide is endothermic. The reaction of the reduced metal oxide maybe endothermic or exothermic, depending on the particular oxide and the degree of oxidation, but this reaction is never sufiiciently exothermic to supply heat for the gasification reaction. In order to supply heat to the gasiiication and when necessary to the steam-oxidation reaction, another portion of the reduced metal oxide is contacted with air to reoxidize the reduced metal oxide and liberate heat. A portion of the heat thus liberated is stored as sensible heat in the metal oxide particles and is transferred to the other reactions by the reintroduction of the reoxidized metal therein. However, application of external heat by indirect or direct means, such as bya furnace or by preheating gases or solid materials, may be practiced without departing from the scope of this invention.

Theupward linear velocities of the gases used tofiuidize the iinely-divided particles may be adjusted in conjunction with vertical iiow so'that particles of ash, which in general will be of lower density than those of the metal oxides, will be entrained and withdrawn with the gaseous efiluent from thev upper portion of the reaction zones, after which ash is separated from the gaseous eliuent by. conventional means such as cyclone separators, scrubbers, etc. In this manner of operation coal and metal oxides are retained in the reaction zone as 'a dense pseudo-liquid mass. In the event that allof the ash cannot be separated in this manner, depending upon the operating conditions used and the character of the carbon-containing material and metal oxide, it may be necessary to remove a portion of the solids from the gasification zone and subject this portion of solids thus removed to mechanical separation methods, such as magnetic separation, elutriation, iioatation, etc. After removal of the ash, this portion of the withdrawn solids is returned to the system.

It' is believed that the invention may be best described by reference to the accompanying drawings which show a process for the gasication of coal in accordance with this invention.

Fig. 1 is a diagrammatic illustration in elevation of an arrangement of apparatus for the gasification of coal or coke to produce a gas comprising hydrogen and carbon monoxide and the subsequent use of the hydrogen and carbon monoxide thus produced as feed gas for theV synthesis of organic compounds. 1 l

Fig, 2 of the drawing is a diagrammatic illus- 4 tration in elevation, partly in cross-section, of an arrangement of apparatus for the gasification of coal and the production of hydrogen in which the coal is gasiiied under conditions such the ash and reduced metal oxide are molten, hereafter referred to as slagging conditions.

Fig. 3 is also a diagrammatic illustration in elevation, partly in cross-section, of a modiiication of the apparatus of Fig. 2 for the gasication of coaland the production of hydrogen under slagging conditions.

The principal pieces of apparatus of Fig. 1 of the drawings comprise a coal gasification zone I3, in which coal is contacted with a reducible metal oxide under conditions such that carbon oxides, primarily carbon monoxide, are produced, an oxidation zone 24 in which reduced metal oxide is contacted with steam under conditions such that reduced metal oxide is reoxidized and hydrogen is produced, a second oxidation zone 3l in which a portion of the reduced metal oxide from gasication Zone I3 is oxidized with air at a relatively high temperature as a means for supplying heat to gasification zone I3, and a synthesis reaction zone 44 in which the carbon monoxide produced in reactor I3 and hydrogen produced in reactor 24 are converted to organic compounds and water.

According to Fig. 1, a iiuidizing or carrying gas, such as steam, methane, recycle gas from the gasification zone I3 or synthesis zone 44, or carbon dioxide, is passed through'conduits 9 and II or conduits 9, I6 and Il' to gasiication reaction zone I3. Solid fuel, such as coal or coke and/or additional iiuidizing gas is introduced into the system through conduit I I as shown. Gases passing through conduit II pick up reoxidized metal oxide, such as magnetite (FeaOi) or hematite (FezOs), from standpipes or conduits 28 and 33. The mixture of finely-divided metal oxide is introduced into the lower portion of gasication reaction zone I3 through conduit I I. A portion of thev mixture may be introduced into the upper portion of the reaction zone I3 through conduit I2, if desired, in order to aid in the dispersion and admixing of the solids in that portion of the reaction zone.

In gasification reaction zone I3 the finely-divided metal oxide is maintained in a fluidized condition, preferably in the form of a pseudoliquid dense phase characterized by an interface between a lower dense phase and an upper dilute phase. This pseudo-liquid dense phase is maintained in reaction zone I3 by controlling the amount of gases introduced into the bottom of reactor I3 and the linear velocity of the gases passing upward through reactor I3, this velocity being between about 0.5 and about 5 feet per second; Coal or coke is introduced into the lower portion of the dense phase in reactor I3 through conduit I4 by means of a standpipe or Fuller- Kinyon pump. Additionally or alternatively to that introduced into conduit II, the coal or coke may b e introduced at a plurality of points longitudinally or transversely of reactor I 3 without departing from the scope of this invention.

It is preferred to introduce coal into the lower portion of the dense phase and the reducible metal oxides into the upper portion of the dense phase in order to minimize classication. By varying the gas velocities and shape of reactor I3, coal may be made to iiow upward and the metal oxides downward in reactor I3, causing countercurrent contact between coal and metal oxides.

The coal or coke is crushed or ground to va relatively iine part-icle size 'prior to introduction into reactor I3. Preferably, the powdered coal (and metal oxides) contains no more `than a minor proportion of weight of material whose average particle diameter is greater than about `250 microns. The pulverization of the coal may be effected by various conventional means, such as by grinding in a ball mill, or by explosion pulverization.

Only a portion or the gas needed to fluidize the nely-divided'contact mass in reactor I3 may be needed to transfer the metal oxides from standpipes 28 and 33 in reactor I3. In such a case, it may be desirable to pass only a portion of the gases from conduit 3 to conduit I I; the remainder which is not needed to carry the metal oxides to reactor I3 may be passed directly to reactor I3 through conduits I3 and I'I and injected therein through a suitable dispersion means, not shown, so as to maintain the fluidized mass under vigorous agitation.

The temperature oi reactor I3 is maintained between about 1000 and about 2000 F., a preferred range with iron and its oxidesbeing between about 1300 and about 1650 F.; such conditions are suitable for the oxidation of the coal by the metal oxides. In this respect it should be noted at such temperature conditions the metal oxides have a partial pressure of oxygen suiicient to oxidiae the coal when the coal is dispersed throughout the mass of nely-divided metal oxide. The gases passing upward through the contact zone are not primarily for the purpose of oxidizing'the coal but merely to maintain the nely-divided metal oxide and the nely-divided coal in a fluidized condition characterized by vigorous agitation and circulation o the contact particles. Reaction pressures range between about atmospheric and about 650 pounds per square inch gage. Preferably, however, a pressure above 100 pounds per square inch gage is employed. The ratio of carbon introduced into reactor I3 with respect to the metal oxide is, in the case of iron oxide, between about 0.05 to about 20 pounds of carbon per hour per pounds of metal oxide calculated as the elementary metal in the reactor, depending on such factors as residence time of reactants and temperature. With iron, vthe metal oxide introduced into reactor I3 is based on the coal fed thereto and is between about.4:l and about 40:1 (pounds of metal oxide calculated as elementary metal per pound of coal fed) Y Metal oxide is continuously reduced in reactor I3 and must be withdrawn either continuously or intermittently and reoxidized. The average residence time of the metal oxide in reactor I3 is maintained between about 5 seconds and about 30 minutes, depending upon the metal oxide used, the operating conditions, etc. The reduced metal oxide is withdrawn from the dense phase of reactor I3 for reoxidation by means of conduit or standpipe 2I. The solids withdrawn from reactor I3 through conduit ZI, for example, may comprise about 90 per cent by weight of the metal oxide or the elementary metal,1 about 9 per cent ash and about 1 per cent coalor coke. The solids withdrawn from reactor I3 through conduit2| are divided into two streams, one solids stream isA passed through the conduit 22 to conduit 23 through which superheated steam is passing at a suiciently high velocity to carry the solids into oxidation reactor 2d. Gases are passed upward through reactor 24I`at a sufficient linear velocity to suspend the'reduced metal oxide-in the pre- 6 fered embodiment of. this invention in a pseudo liquid dense phase condition as described with respect to reactor I3. Operating conditions are maintained ln reactor 24 such that the reduced metal oxides, either the elementary metal or a lower oxide than that introduced into reactor I3,

is reoxidized to a higher oxide and hydrogen is produced. Hydrogen, together with unconverted steam which is less than about 30 per cent at 1500 F., is removed from reactor 24 through conduit 26. Reoxidized metal oxide is withdrawn from reactor`24 through conduit Il or standpipe 28 and returned to reactor I3 through conduits I I or I2.

The temperature maintained in reactor 2471s usually about the same as that maintained in reactor I3, but may vary as much as F. above or below that temperature, and a pressure substantially the same as that prevailing in reactor I3V is employed. With iron or iron oxide, the ratio of steam to solids calculated as the elementary metal is between about 0.4: 1 and about 1.5:1 calculated as pounds of steam per pound of metal.

Another portion of the material withdrawn vfrom reactor I3 through conduit 2l is passed to conduit 29 where it is picked up by compressed air and transferred to another oxidation reactor 3l. This portion of the solids removed from reactor I3 is adjusted such that by exothermic oxidation thereof in reactor 3| a heat balance is maintained over the system of reactors I3, all and 3I. As in reactors I3 and 2d, in the preiferred embodiment of this invention the nelydivided solids in reactor 3i are maintained in a pseudo-liquid dense phase condition by adjusting the upward linear gas velocity therein. The reduced metal oxides in the dense phase of reactor 3l are oxidized to higher oxides and the temperature is permitted to rise by virtue of the exothermic heat of reaction at least 50 to about 500 F. higher than the temperature of reactor I3. is removed from reactor 3| through conduit 32 and vented to the atmosphere. flue gas may be recycled, by means not shown, to aid in the iluidization of the solids inreactor 3|, if desired. The flue gas is relatively high in temperature and this heat may be recovered by passing the gas through a waste heat boiler (not shown) or by indirect heat exchange with the gases inl conduit Il or other process streams without departing from the scope of this invention. The pressure in reactor 3| is substantially the same as in reactors I3 and 24, Reoxidized metal at a relatively high temperature is removed from 3l through conduit or standpipe 33 and returned to reactor I3 through conduits Il and I2 as previously discussed. The heat of these solids preheats the gases in conduits Il and I2 and maintains the temperature of reactor I3 at the desired level. Solids passed from reactor I3 to reactor 2d maintain the temperature therein at the desired level. 1f desired, a portion of 'the solids may be passed directly from reactor Flue gas consisting essentially of nitrogenk A portion of the from' reactor 'i I 35 toy reactor 31If. This modicaf tion miniiniZes-l-tlfiev` temperaturef required" .inV re:-Y actor y3'I'. Y

In order to minimize contaminationV of the eiliuentvof reactor I3" with nitrogen which are occludedA in the solids removed-from reactorV 3'I', a stripping. gas, such Aas-steam',v is introduced. into'standpipe 33 to strip nitrogen :from the Isolids.. therein. The solids passing through1conduitl2'l maybe` stripped' with a suitable gas', such aslA steamY or carbon dioxide, to minimize the' oc clusionl of carbonmonoxide by thel solids.

In order to prevent the'build-up of 'ashf in` the system, a portion of the solids in conduit 2I may bepassed therefrom to: an ashremovalmeans 'lbytransfer linesl 36.- Ashrremoval means l37| f may compriseanyisuitable appara-tus and, equipment'for vremoval of ash from the reducedV metal oxides, such as conventional settlingchambers,y magnetic separators, elutriation means,l` etc'. Ash is'removed from unit 31 through conduitnlll and the Areduced-metal oxides Yare returned' to .conduit or standpipe-Y2I through transfer means 36.

The eluent from unit I3 containing carbonA oxides'is withdrawn therefrom from conduit I8 and may be recycled through conduits ISV-and'` II for furtherl conversionthereof and as an aidl in maintaining the finely-dividedV solids in the fluidized condition in unit I3. A cyclone sepY arator or a filter may be positioned within or external of reactor I3 to remove nely-divided'entrained solids from the eiiluent removed throughv conduit I8. A portion of the eiuent containing carbon oxides may be removed from the system through conduit 20 for separate use or other purposes. For example, when this eiiluent-contains an appreciable amount of carbon dioxide, it may be passedthrough another reaction acne containing finely-divided coke or coal inY a fluidized condition at an elevatedvr temperature to convert a portion of the carbon dioxide to carbon monoxide. The carbon monoxide thus produced may be utilized in the manner described hereinafter.' At a reaction temperature of 1500" F. in reactor I3', the mol ratio of carbon monoxide to carbondioxide is about 2:1, and-at higher temperatures an increase in Vcarbon monoxide is obtained.

Carbon monoxidev and hydrogen are passed' through conduits I8 and 2B, respectively, to conduit 2 in which they are combined'in the appropriate proportions to provide a synthesis feed. gas of the desired' composition, usually a mol ratio of hydrogen'to carbon monoxide'of about 1'11 to about 3:1. Since th'eseV gases are at aA higher temperature than isnecessaryv forf the' synthesis reaction, andsince in some cases, es pecially when there areno cyclone separators or filtersl used to separate solids fromv the effluent gases, they mayl contain entrained solids, such as ash, the gases are passed to a scrubber 4I in which they are contacted with a liquid scrubbing. medium', such as water or oil. The scrubbing medium cools theeiuent toY the desired tern-I perature and removes entrained solids and con-- densed steam from the gases. The gasesare cooled to a temperature of about 150i in the' scrubber 4I. Cooled synthesis'gas, comprising hydrogenV and carbon .monoxide is passed. throughconduit 42 and-cooler 43.110 synthesis: reactor 44.

In a modification of this invention, only` the.. effluent stream in conduit 26. is1scrubbedand, cooled tot remove water and. entrained--solids:.

65..,denser1v 52 Lto' an:V accumulatorY 53.

8. I8by-means-ofa cyclone separator or' a, filter: Inthisy manner, the heat of the efiiuent 1n con-v duit: I8is-retained and the' effluents then combined and'passed to synthesis reactor-44.

Scrubb'er 4I may-be operated atielevatedpressures; when using'vvaterV as the scrubbing medium, under conditions Ato remove at least a portion o! the carbon dioxide from the effluent, ifA desired: In synthesis reactor 44, the synthesis gaspasses 10 upwardlthrough amass of finely-divided contact material' maintained therein in apseudo-liquid. dense' phase' conditionY under appropriate. condi'- tions of temperature and pressure,. such. that; organic compounds4 havingmore `than one Vcarbon.-

` atomA permoleculeare produced. The contact'.

material may comprise any suitable: hydrogena-4 tion catalyst,. such as iron,4 nickeL. or cobalt; When using. a contact material comprising'iron, a temperatureibetween about .450 and about 7509" F; isemployed', and when using a'contact material comprising cobalt or nickel a temperature below: about 450 E. is employed. The pressureof re'- action may be between about atmospheric and about-:500 pounds per squareinch gage, prefere .ably 'at at pressure slightly lower than thepresf sure;of;reactor.t I3. Accordingto4 one embodimentV ofthis invention, theV contactmaterial in synthesis;reactor.A 44'- may be the; same as the. material used in: gasification reactor. I3. Under such circumstances, thet reduced metal oxides,

from reactor I3A are passed therefrom throughv conduits: 2I and 49 tothe; feed inlet line,42 of. synthesis-reactor 44. Contact material isWthfdrawn fromzthedense lphase of synthesis reactor 35. 44` through standpipeV 46'and may be recycled through conduits. 41 and 42 and.cooler.43 in orderv to maintain the temperature at the desired level in reactor 44. Other conventional methods for cooling reaction chamber 44 may be employed without departing from the yscope of this invention.v Since the contact material used in synfv thesis reactor 44- may become deactivated as. the result of the accumulation of carbonaceous deposits; thereon, such as waxes and relatively;

45 high-boiling organic compounds, and as the` ref sult of oxidation, this material maybe Withdrawn fromreactor 44- and passed to gasification reactorr I3'throughconduits 46,48, 9, I6 and I'I,.as;sl1own, or to oxidation reactorsy 24 and 3I bymeansnot 504 shown. In gasification chamber I3 the oxidizedffrtion,l gasification chamber. I3 Acomprises in. part a regeneration'chamber for the contact material` remoyedfrom. synthesis reactor 44. When .the deactivated catalyst fromireactor 44 is passed tot. oxidationY chambers-v 24` and 3|, the waxes,

(h-etc'. are removed by oxidation.

A1. reaction effluent comprising organic com-- poundsg including oxygenated compounds and hydrocarbons, is removed 'from synthesis reactor Mnthrough` conduit 5I and is passed through con-- Condenser 52 may'comprise'a singleror: series of cooling and` condensing units. Thev eluent is cooled'in con-- denser: 52 .to a'temperature-.below"about"100"E; at theipressure prevailing' in 'the vsynthesis reactor.'

70144'.` Water-and organic compounds which have beenliqueedi are'. collected in accumulator. 53 andmaybawithdrawn therefrom through conduitzB--forffurther treatment and separation'in amannerfknown to'thcse skilledin thev art.

Solidsfarezremovedxromzthe enluentnnxconduit: -UncQndensed.vapors;including;hydrogen,car--` bon dioxide, unreacted carbon monoxide and some relatively low-boiling hydrocarbons, are removed from accumulator 53 through conduit 54 and may be recycled to conduit 9 through conduit 51 as the uidizing gas, or may be recycled to conduit 2i by means of conduits 58 and 59 to supplement the feed to synthesis reactor 44. A portion of this gaseous eiiluent from accumulator 53 may be vented through conduit 58 to prevent the build-up of undesirable gases in the system, such as nitrogen, and/or passed to a carbon dioxide absorption system (not shown) for removal of carbon dioxide from the gases. The carbon dioxide thus recovered may be recycled to conduit S, or conduit i I, or conduit 2l, as desired.

In the preferred method of operation of the various reaction units, the inely-divided contact material is maintained in a pseudo-liquid dense phase condition. However, these units may be operated by varying such factors as the shape of the reactor and the linear gas velocities, such that the contact material is entrained in the gases flowing therethrough. Velocities above about feet per second are employed for such operations. In this latter type of operation, means must be provided externally of the reactor for separating contact material from the eiiluent and for circulating the thus-separated contact material to the same or other reaction zones in the process. In this respect, reaction unit I3 may be operated with a linear gas velocity such that ash is entrained in the gases and passes overhead while the contact material, such as iron oxide, is substantially all retained in the reactor as a pseudo-liquid dense phase. The entrained ash is then removed from the gaseous eiliuent in scrubbing unit lil.

The solid oxygen transfer agent or contact material of the present invention is a nely divided powder comprising a metal'oxide, reducible under the conditions of operation. Various oxides may be used for transferring oxygen to the coal gasiiication reactor I3. Such contact material comprises oxides of iron, cobalt, nickel, molybdenum, manganese, barium, vanadium, chromium, copper, and mixtures thereof. Copper oxides are particularly desirable when used in admixture with other metals or metal oxides, such as iron oxide.

Since the heat supplied to gasilication unit I3 from oxidation reactors 2li and 3i by transfer or" finely divided contact material therebetweerrit is desirable and particularly convenient to incorporate with the oxygen-carrying contact material a relatively inert or non-reactive finely divided heat-carrying material, such as alumina,v silica, magnesia, bauxite, bentonite, sand, ash, etc. These heat-carrying materials may be present as separate particles with the oxygen-carrying material, or may be used as supports in the conventional manner with such oxygen-carrying materials. These materials abe sorb the heat released in oxidation reactor 3| as sensible heat transfers that heat to reactor 2s and gasification unit I3, where it is utilized. When a heat carrier material is employed in con- .junction with separate oxygen carrier, the amount ci heat-carrying material will be substantially greater than the amount of active oxygen-carrying material. As much as 5 to 40 times as much by vweight of heat-carrying material as oxygencarrying material may be used.

The use oi a large quantity of inert heat-carrying material in the contact material renders the process particularly suitable for the use of cheap natural ores which contain originally a large proportion of inactive material. A naturally occurring montmorillonite type clay, such as Ittawamba clay, is particularly suitable for this purpose. IttaWamba clay contains about 5 weight per cent FezOs and about 1.3 weight per centr T102. A montmorillonite type clay may also be used as a support for oxygen-carrying material, since it is suitable as a heat ycarrier and has particularly desirable flow characteristics for use in iiuidized systems. As previously indicated, the oxygen-carrying material, including any diluentr therein, may be passed from gasification reactor I3 to synthesis reactor M as catalyst material and may be recycled therefrom backto gasification unit I3. In this manner of operationthe oxygen-carrying material supplies the oxygen for the gasification reaction and also serves in its reduced form as the catalytic agent for the synthesis reaction. In such a modication Alan Wood ore is suitable for use as both oxygen-carrying material and as a catalyst for the synthesis reaction. This ore contains about 1 to 2 per cent alumina, 1 per cent silica, 0.4 to 1 per cent titanium oxide, and the remainder F8304.

The oxygen-carrying material may be selected from materials which have a catalytic eiect upon the gasiiication reaction or a catalytic material may be combined or admixed with the oxygen-carrying material. Such materials which have a catalytic effect upon the gasication reaction comprise nickel, chromium, vanadium, ruthenium, etc., and their oxides. A promoting ingredient may also be incorporated with 'the oxygen carrier and/or catalytic material. The promoting material may have a benecial effeet on the gasication reaction, and when the oxygen carrier is also used in the synthesis reaction they promoter may have a benecial effect on the synthesis reaction. Such promoting materials comprise diicultly reduoible metaloxides as barium oxide, alumina, silica, titania, thoria, manganese oxide, and magnesia. example, when using Alan Wood ore as the oxygen-carrying material, heat-carrying material, and catalyst, for the synthesis reaction, a suitable promoter, for example barium oxide or thoria, may be incorporated therewith by fusion ortother manner known to those skilled in the ar As previously discussed, a suitable proportion of the circulating solids may constitute a heat carrier, and for this reason it may be desirable to allow ash to build up in the system Whereby circulated ash serves as a heat carrier. In this modiiication of the invention the ash mai7 comprise 50 per cent or more of the solids withdrawn from reactor I3 through conduit 2i. vExcess oxygenL carrier may also be used as the heat carrier material. Thus, only a small proportion of the oxygen carrier material actually'supplies oxygen for the gasication reaction, the remainder being present primarily as a means of passing heat to and from the various reactionzones.

Although solids are passed to and from the various reactio-n zones by means of standpipes of suilicient length to overcome pressure drops, other means known to those skilled in the rart may be employed, such as by the use of conventional solids pumps, for example a Fuller-Kinyon pump.

The modification represented' in Figure 2 is particularly applicable to solid fuels having a or slurryof solids :and molten material.

llow ashi'fusion temperature iand .a high :ash con- 'ftent. ."According to .'F'igure '.2 of .the drawings, VJa..`cra.rr.ying or luidizingigas such .as steam, .car- :iion dioxide, vrecycle `gas or methane, .is passed through conduit .16 fto kgasiilcation .chamber 8|. 'zMetal .oxide Lactingas .anA` oxygen carrier is ini'troducedfromconduitsi9'1 and |84 .into the gas :flowing 'through conduit 16 .and is entrained in .thegaseouspmixture The "velocity of the gases in conduit 16 .is :such .that the 4oxygen-.carrying :material includingv any..heat .carrier .material :is passed .tto gasiiication .unit .8| .the .construction Aof whichris similar to fthe combustion .chamber .3:15a .conventional slaggingtype boiler. andisbuilt Lito .withstandisubstantial:.superatmospheric; pres- ;'sums Coalisrintroduced into conduit" through conduit .T8 .and a 'dispersing gas .is introduced .;:into.,conduit`1l. The .dispersing gas rcarries the coaland .oxygen carrier ."including heat .carrier .material through conduit 11 A:tozan .injecting or .mixing .device Vlf) .and thence into'ahigh 'velocity 4IchamberrBZ ofrgasification unit 8|. vThe .dispers- :inggas introduced through conduit Tl may be 'the-samefora'diiferent gasthan that used for :carrying thefsolidsin conduit 16. The-temperature of-igasiiication unit 8| :is -sufcientlyhigh that the reduced metal oxide or carrier matelriaLfincluding 'heat-carrying material and ash, lbecomes ',molten. .Temperatures :above vabout ..1700-F..a`re preferredzfor this purpose; although .the :exact temperature "will .depend upon .the .melting A.points ofthe solids. .Oxgen vfrom .the -carrier .material :reacts with the coal .passing .downwardly .through high velocity chamber 8.2 '-.under -conditions .'such ithat `carbon dioxide .and .carbon:.m'onoxide'are4 produced and the `reduced carrier becomes molten. The .resulting mixture ..0f moltenfandreducedzcontact material, ash, and `:gaseousproducts 'of the process, passes Vfrom'high velocityrchamber V82 .into -a separation chamber .-83 :of iunitfBL :In separation chamber 83, .the -gaseousproducts of the process .are separated ,from 4liquefied ash and :reduced .contact matetrial. 1 Reduced vcontact material .forms -.a lower Y liquid ,phase "86 -in` separation .chamber `83 tand .the ash forms anup'per'liquidrphase 84. inicham- 'ber-83. The operations of .unit 8| may be such .thatonlytaportionbf thesolids in .the .contact material becomes..molten, and insuch manner .of.operation.-.liquid phase-86 comprisesa mixture Azsuitable ilux may be admixed or combined with-the contact material or:.coal to materially reduce. the .melting .point-of -any .component of the solids. `.Such ,.iluxing .materials .may comprise, '.for .example, llimestone or borax. It is particularly de- .sirable to use Vsuch fluxing-m'aterials to ;.reduce .the melting point of '-thei-ash vin the coal. The gaseous products, `such as carbon dioxide 'and .carbon monoxidaare withdrawn from chamber 83 .through anoutletconduit '81. Liqueiied ash .withdrawnirom chamber 83through conduit V.l|.i.or.disposal. :Liquefed-.contact material,` or a slurry of v.liquid and .solid .contact material, is .removed from .chamber -83 through Yconduits .89 and.98.

`.[tis .desirable to .employ a relatively lowmeltingoxygen .carriermaterial in this modification. "For-example, 4a .copper alloy containing "at least '25 per centtin, .or.at.least .40..per cent zinc, and up`to'5.per.cent .nickel may vbe employed as both an oxygencarrierandheat carrier, as'this mate- 'rialbecomes molten at about l600 F. Various .other eutectic -or alloycompositions may be used, Ltknownto vthoseiskilledin theart.

oxidize all of the metal oxidizing agent. ever, the metal is-not necessarily oxidized to its heater .|01

1'2 .A `portionof the .liquefied contact material .is introducedintoa hydrogen producer 92 through .dispersionmeans 9|. In hydrogen vproducer .92 liquid .reducedmetal oxides are sprayed .downwardly countercurrently to an upward flowing stream .of steam. .Steam .ris introduced into the lower portion of hydrogenproducer 92 .at aplurality .ofpoints .through conduits 93 as shown. The steam .reacts under the conditions maintained .therein with the'reduced `metal oxide or -foxygen vcarrier to Yproduce .hydrogen and to .oxi-

dize .the.metal. Upon oxidation the metal forms .finely divided solidparticles which .settle at-the Vbottom of Ahydrogenproducer 92 andare withdrawn therefrom by means ,of a conventional standypipe for reintroduction into 'conduit 16 :as

.previously described. Hydrogen producer 92 is .maintained .atatemperature between the melting points .of the reduced metal oxide vstream introduced .therein andthe solidreoxidized metal whichis withdrawn therefrom. This temperature is maintained'approximately the same -oras Amuch as.1501F. aboveor-below thetemperature of -gasicationunit-Bl, hutnhigher or lower temperatures may be employed, depending on the particular operating technique of the process. Anexcess amount of steam is used to completely Howhigheroxide.

Another'portion oi the liqueed contact material isremoved from chamber 83 through .conduitv98 and isintroduced into heater |0| .through distributor 99. The molten .metal is sprayed .downwardly in heater '|0| and .the molten parl.particles being formed containing the heat of .reaction -as sensible heat.

Reoxidized .oxygen- .carrier in finely divided form and at a relatively .high temperature .is withdrawnfrom .heater |0| .through conduit |04 .and is introduced intocon- .duit .16 as `previously described. ,.Flue gas .is .re-

moved from heat-er |0| through .conduit |03.

Flue gas may be recirculated .through heater ||l| or .heatfexchanged with .other `fluid streams of the process. The proportion of the liqueiied contact material passed to hydrogen producer 92 and is controlled such that a suflicient amount of heat is supplied to the system to maintain gasication unit 8| and hydrogen producer 92 at the desired temperature. In this respect the operation of the modification of Fig. 2 is similar to the voperation of the modication of Fig. 1.

The hydrogen produced in hydrogen producerv 92 is withdrawn overhead through conduit 94 and is combined with the carbon monoxide in conduit 81 in the appropriate amount so as to produce a synthesis feed gas having the desired hydrogen to carbon monoxide ratio. This feed gas maybe passed to a `synthesis-reactor similar to that .shown in the embodiment of Fig. 1. If desired, a'portion of the hydrogen may be withdrawn from the system through conduit for separate use and treatment.

Figure 3 of the drawings is a diagrammatic illustration in elevation of a modication of the process vdescribed with respect to Figure 2, and

.consequently .only a brief discussion thereof will 13 be made. In the modification of Figure Y3, the oxidation reactors are in series. As in Figure 2, the modiiication of Figure 3 is applied exceptionally well to solid fuels having a low ash fusion temperature and/or high ash content.

A carrying or luidizing gas, such as carbon dioxide, steam, ror meth-ane, is passed through conduit |25 to gasication reactor I3I. The carrying gas picks up the finely divided om'dizing agent from conduit or standpipe |5| and the resulting mixture passes to gasification reactor |3| as previously discussed with respect -to Fig. A dispersing gas such as steam is introduced into gasification unit |3| through conduit I2?, and coal or coke is introduced into conduit |21 through conduit |28. The mixture of oxidizing agent, coal, and dispersing gas is introduced by means of injection and mixing means |25 into the high velocity section |32 of gasication unit |3I. Gasication unit |31 is similar in construction to that described with respect to Fig. 2. The coal or coke is oxidized by means of the oxidizing agent such as iron oxide to produce carbon monoxide at a temperature preferably above about 1700 F. A dispersed phase of solids passes downwardly through high velocity section |32 into separting section |33 of gasiiication -unit |3I. At the temperature of operation, the ash remaining from the oxidation of the coal or coke, and. the reduced oxidizing agent, are liqueed. An upper liqueed ash phase |34 and a lower liquefied reduced oxygen carrier |36 form in the lower portion of separator |33. The liqueed or molten ash is withdrawn from separator |33 through conduit |31 for disposal. Liqueed oxidizing agent, or a mixture of a metal and its oxides, is passed from gasication unit |3| through conduits |38 and |39 to the lower portion of an oxidizing unit bil, the construction of which is similar 'to a Bessemer converter and built to withstand pressure. The molten mix-ture forms a liquid layer I 44 in oxidation unit Ilil. Air is bubbled through the liquid oxygen-carrier by introduction at a 4plurality of points through conduits |42. Flue gas comprising nitrogen is removed from oxidation unit or heater |4| through conduit ILES. The molten mixture or" oxygen-carrier is partially oxidized at a temperature at least 50 to about 500 F. above the temperature prevailing in gasification unit I3I. Under these temperature conditions and with the appropriate degree of oxidation the mixture remains fluid in oxidation unit |4| and is removed therefrom through conduit It@ and introduced into a second oxidation unit |48 by means oi distribution and dispersion means |41. The fluid oxidizing agent is sprayed downwardly in oxidation unit IfiI and countercurrently contacts an upward iiowing stream of steam introduced at a plurality of points into reactor |4S through conduit |49. The temperature in oxidation unit |48 is about the same as the temperature of oxidation unit MI and sufficient steam is introduced to completely oxidize the oxidizing agent to an oxide, although not necessarily the highest oxide, whereby nely divided solid particles of oxygencarrier are collected in the lower portion of oxidation unit Hit. The reoxidiaed solid oxygencarrier is passed from oxidation unit |43 through a standp-ipe or conduit |5| to conduit |26 as previously described. The reaction of the oxidizing agent, such as the elementary metal or a lower metal oxide, with steam produces hydrogen. The hydrogen is removed from oxidation unit |48 through conduit |52 and after removal of Vunconverted steam by condensation (not shown) is combined with the carbon monoxide in conduit |40 in the appropriate amount to for-m a suitable synthesis feed gas comprising hydrogen and carbon monoxide. The synthesis feed gas is passed to the conventional synthesis equipment as illustrated in Fig. 1.

The amount of oxidation effected in unit |4| is regulated such that the heat of reaction required in unit |3| and unit |48 is supplied by the oxidation effected in unit I4I, and the required amount of hydrogen is produced by the oxidation effected in unit |43. In another modication of Fig. 3 steam rather than air may be introduced into unit |4I, and air rather than steam may be introduced into |48. In such a modification hydrogen is withdrawn from-unit I4! through conduit |43 and is combined with the carbon monoxide in conduit |40. Flue gas comprising nitrolgen is removed from oxidation unit |48 through ,conduit I 52 and is vented to the atmosphere, used 'as a luidizing gas, or recirculated, `as desired.

In the modification of Figs. 2 and 3 a low'melting oxidizing agent is preferably used, for example, zinc, bismuth, tin, and lead, and their oxides, or these metals may beA combined with higher melting metals such as copper to form alloys or eutectics having relatively low melting points.

Specific reference may be had to my prior and copending application Serial No. 751,728, led June 2, 1947 for general background material and methods of pulverizing and handling coal or coke.

Certain valves, coolers, heaters, pumps, accumulators, storage vessels, conduits, etc., have been omitted from the drawings as a matter of convenience and clarity, and their use and location will become apparent to those skilled in the art. It is not intended to limit any particular location of inlets and outlets of the apparatus shown in the drawings. The examples andtheory in connection with the invention are offered as illustrations and should not be construed to unnecessarily limit the invention.

I claim: l l

1. A process for the gasication of solid carboncontaining material which comprises introducing finely-divided reducible metal oxide selected from at least one of the group consisting of the oxides of iron, cobalt, nickel, molybdenum, manganese, barium, vanadium, chromium and Vcopper and solid carbon-containing material into a reaction zone, suspending such finely-divided reducible metal oxide and said solid carbon-containing material in a gasiform fluid substantially free from free oxygen passing through said reaction zone, maintaining said reaction zone under endothermic conditions and at a temperature such that carbon is oxidized. to carbon monoxide as the principal reaction by reduction of said metal oxide, withdrawing from said reaction zonereduced metal oxide, reoxidizing by contact with free oxygen said withdrawn reduced metal oxide under exothermic conditions and at a higher temperature than maintained in said' reaction'zone, reintroducing the reoxidized metal oxide into said reaction zone at a temperature above the temperature level maintained therein such that heat is supplied to said reaction zone thereby, and with- Y drawing from said reaction zone an eilluent ccmprising carbon monoxide as a product of process, said reducible metal oxide being the principal source of oxygen for the oxidation of carbon to carbon monoxide.

2. A process for the gasiiication of solid vcarboncontaining materialwhich comprises introducing -.so1id carbon-.containing material. into. a reaction lone, passing .a vgasiform fluid substantiallyiree `from free oxygen upwardly in-saidreaction zone through a .mass .comprising said .finely-divided .reduciblemetaloxide and .solid carbon-containing .materialat a velocitysufcient tomaintainsaid .mass in a pseudo-liquid uidized condition where- .by nely-dividedsolids are circulated throughout .a dense phase of iiuidized solids, maintaining. said .reacion zone under exothermicconditions and at .a .temperaturesuch that `carbon is oxidized .to carbon monoxide as the principal reaction .by Yreduction of saidmetal oxide, withdrawingirom said reactionzone finely-divided reduced metal oxide, .reoxidizing .by .contact with .free/.oxygen -saidreduced metal oxide under exothermic conditions and at a higher .temperature than maintained in said reaction zone, returning. reoxidized metal oxide Yto said reaction zone at a .temperature vabove the temperature level maintained vtherein such that heat is supplied .thereto and withdrawingfrom said reaction zone Vanefiluent comprising carbon monoxide as a productof the process, said reducible metal .oxide beingthe principal source ofoxygenffor the. oxidationof carbon to ,carbon monoxide.

.The process of rclaim 2 in which a `portion of said eiliuent withdrawn from said reaction zone .isrecycled asat least a portion of saidgasiform Liiuid.

.4. .The .process of claimZin whichsaid nelydivided .reducible metal oxideis introduced into the upper portion of said .dense phase andsaid lnely-divided solid carbon-containing .material fis introducedinto the lowerrportion of said dense phase.

15. The process of c1aim'2 in which said reducible metal oxide comprises an iron oxide.

6. The process of claim12 in which said reducible metal oxide comprises as initially introducedinto theirprocess an iron-containing ore.

'7.'The process of claim`2 in which reducible metal oxide comprises a copper oxide.

8. A processforthe'gasication'of'solid carboncontaining material whichcomprises continuously introducing nely-divided reducible metal oxide Vselected from at least one ofthe group consisting of the oxides of iron, cobalt, nickel, molybdenum, manganese, barium, vanadium, chromium and copper and'solid carbon-containing material into the lowerportion of a reaction'zone, entraining said finely-divided reducible metal oxide and'solid carbon-containing material in an upwardly flowing gasiform fluid substantially free from.free oxygen in'said'reaction zone, maintaining the linear gas velocity of'said gasiform'iluid above `about ve feet per second,l maintaining said re- 'action zone .under endothermic vconditions and at Ya"temperature .such that carbon is oxidized to Acarbon monoxide astheprincipal reaction by reduction ofsaid metaloxide, withdrawing agase- 'ous eluent comprising carbon monoxide and en- -trainedreduced metal oxide from said reaction zone, separating reduced metal oxide from said eiliuent, reoxidizing by .contact with free oxygen the reduced metal oxide thus recovered under exothermic conditions and at a tempera-ture above the temperature of said reaction zone, returning reoxidized metal oxide to said reaction zone at a temperature above the temperaturelevel maintaine'd therein such thatheat. issuppliedthereto,

' 16 and recoveringsaid carbon monoxide as a product of the process, said metal oxide being therprincipalsource of oxygen for the oxidation of carbon to carbon monoxide.

9. A process for the gasification of solid carboncontaining material which comprises injecting nely-divided reducible metal oxide and solid carbon-containing material into a rst reaction zone by .suspension in a gasiform fluid substantially free from free oxygen, maintaining said `rst reaction zone under endothermic conditions and at a temperature such that carbon is oxidized to a carbon oxide as the principal reaction by reduction of said metal oxide and such that reduced metal oxide and ash thus produced are liquefied, collecting said liquefied reduced metal oxide and ashdiscarding liquefied ash, passing said liquefied vreduced metal oxide to a second reaction zone in which reduced metal oxide is reoxidized under exothermic conditions and at a temperature above that maintained in said first reaction zone to form finely-divided metal oxide particles, recycling from said second reaction reoxidized metal oxide in the form of finely-divided particles to said rst reaction zone at a temperature above the temperature level maintained therein to supply heat thereto, and withdrawing from said rst reaction zone an effluent comprising a carbon oxide as a product of the process, said reducible metal oxide being the principal source of oxygen for the oxidation of carbon to a carbon oxide.

10. The process of claim 9 in which said reducible metal oxide comprises an alloy containing tin and copper.

11. A continuous process for producing a gas rich in hydrogen and carbon monoxide which comprises passing a gasiform fluid substantially free from free oxygen upwardly in a rst reaction zone through a mass comprising finely-divided reducible metal oxide and coal at a velocity sucient to maintain said mass in a pseudo-liquid Iiuidized condition, maintaining said rst reaction zone at a temperature such that carbon is oxidized to carbon monoxide as the principal reaction by the reduction of said metal oxide, said reducible metal oxide being the principal source of oxygen for the oxidation of said carbon to carbon monoxide, separately Withdrawing from said first reaction zone nely-di- Vided'reduced metal oxide and an effluent comprising carbon monoxide, passing a portion of said withdrawn reduced metaloxide to a second vreaction zone, passing steam upwardly in said secondreaction zone through a mass comprising nely-divided reduced metal oxide at a velocity sufficient to maintain said mass in a pseudo-liquid .fluidized condition, maintaining said second reaction zone at a temperature such that saidre- .duced metal oxide is reoxidized by reaction with steam to produce hydrogen as the principal reaction, the combined reactions of said rst and said second reaction zones being endothermic, separately withdrawing from said second reaction zone finely-divided reoxidized metal oxide and an effluent comprising hydrogen, combining the effluent from said first reaction zone with the eiiluent from said second reaction zone to form a gaseous mixture comprising hydrogen and carbon monoxide as the product of the process, passing another portion of said reduced metal oxide from said rst reaction zone to a third reaction zone, passing air upwardly in said third reaction zone through a mass comprising finely-divided reduced metal oxide at a velocity sufficient to maintain said massin a pseudo-liquiduidized condition whereby said reduced metal oxide is reoxidized at a temperature above that maintained in both of said first and said second reaction zones and heat is liberated, and withdrawing reoxidized metal oxide at a relatively high temperature from said third reaction zone and passing same to said rst reaction zone at a temperature above the temperature level maintained therein as means for supplying heat of reaction thereto.

12. The process of claim 11 in which said gaseous mixture of hydrogen and carbon monoxide is passed to a fourth reaction zone in which hydrogen and carbon monoxide are converted to or- -ganic compounds including methane, removing an efiiuent from said fourth reaction zone comprising unreacted hydrogen, methane and higher boiling organic compounds, separating unreacted hydrogen and methane from said effluent, and passing said unreacted hydrogen and methane to said rst reaction zone as at least a portion of the gasiform fluid. I

13. The process of claim l2 in which reduced metal oxide is passed from said rst reaction zone directly to said fourth reaction zone as a catalyst for the conversion of hydrogen and carbon monoxide to organic compounds, and withdrawing metal oxide from said fourth reaction zone and passing same to said first reaction zone.

14. A continuous process for the production of r a gaseous mixture rich in hydrogen and carbon monoxide which comprises injecting finely-divided reducible metal oxide and coal into a first reaction zone with a gasiform fluid substantially free from free oxygen, maintaining said iirst reaction zone at a temperature such that carbon is oxidized to carbon monoxide as the principal reaction by the reduction of metal oxide and such that reduced metal oxide and ash are liquefied, said metal oxide being the principal source of oxygen for the oxidation of carbon yto carbon monoxide, collecting liqueed ash and reduced metal oxide, discarding liquefied ash, passing liquefied reduced metal oxide to a second reaction zone, passing air upwardly through said liquefied metal oxide in said second reaction zone under conditions such that reduced metal oxide is reoxidized under exothermic conditions, maintaining a temperature in said second reaction zone above the temperature maintained in said iirst reaction zone and suiiiciently high such that metal oxide is maintained in a molten condition, removing molten metal oxide from said second reaction zone and introducing same into the upper portion of a third reaction zone, passing steam upwardly in said third reaction zone countercurrently to a downiiowing stream of metal oxide under conditions such that metal oxide is oxidized by reaction with steam to produce hydrogen as the principal reaction, maintaining a temperature in said third reaction zone such that all the metal oxide is solidified upon oxidation, withdrawing iinely-divided metal oxide particles from said third reaction zone and passing same to said iirst reaction zone, and withdrawing carbon monoxide from said first reaction zone and hydrogen from said third reaction zone and combining same as the product of the process.

15. A continuous process for the production of a gaseous mixture rich in hydrogen and carbon monoxide which comprises injecting finely-divided reducible metal oxide and iinely-divided coal into a iirst reaction zone with a gasiform fluid substantially free from free oxygen, main- 18 taining said rst reaction zone at a temperature, such that carbon is oxidized to carbon monoxide as the principal reaction by the reduction of said metal oxide and such that metal oxideand ash are liqueiied, said metal oxide being the principal source vof oxygen for the oxidation of carbon to carbon monoxide, collecting liquefied reduced metal oxide and ash, vdiscarding liqueiied ash, passinga portion of said liqueed reduced metal oxide to the upper portion of a second reaction zone, passing steam upwardly in said second reaction zone countercurrently to a downwardly flowing stream of reduced metal oxide under conditions such that reduced metal oxide is oxidized by reaction with steam to produce hy-l drogen as the principal reaction, the combined reactions of said rst and said second reaction zones vbeing endothermic, maintaining a temperature in said second reaction zone such that all the reoxidized metal oxide is solidiiied to form iinely-divided particles, removing hydrogen fromA said second reaction zone and combining same with carbon monoxide from said first reaction zone to form a gaseous mixture as the product of the process, passing another portion of said liqueed reduced metal oxidefrom said first reaction zone to the upper portion of a third reaction zone, passing air upwardly in said third reaction zone countercurrently to a downwardly flowing stream of reduced metal oxideunder conditions such that reduced metal oxide is oxidized with the liberation of heat, maintaining a temperature in .said third reaction zone above that temperature maintained in' both of said rst and said second reaction zones and such vthat all the reoxidized metal oxide is solidied to form iinelydivided particles, and withdrawing finely-divided metal oxide from said second and third reaction zones and passing same to said first reaction zone, the temperature of said iinely-divided metal oxide passed from said third reaction zone to said first reaction zone being above the temperature of said first reaction zone suchv that heat is supplied to said iirst reaction zone.

`1t. A process for producing a gas rich in hydrogen and carbon monoxide which comprises in troducing nely-divided reducible metal oxide and solid carbon-containing material into a first reaction zone, suspending finely-divided reducible metal oxide and solid carbon-containing material in a gasiform fluid substantially free from free oxygen in said rst reaction zone, maintaining said first reaction zone at a temperature such that carbon is oxidized to carbon monoxide as the principal reaction by the reduction of said metal oxide, said reducible metal oxide being the principal source of oxygen for the oxidation of' said carbon to a carbon oxide, withdrawing reduced metal oxide and a gaseous effluent comprising a carbon oxide from said iirst reaction zone, passing reduced metal oxide from said first reaction zone to a second reaction zone, suspending reduced metal oxide in said second reaction zone in a stream -of steam under conditions such that reduced metal oxide is reoxidized by reaction with steam to produce hydrogen as the principal reaction, the combined reactions of said rst and said second reaction zones being endothermic, withdrawing reoxidized metal oxide from said second reaction zone and returning same to said first reaction zone, combining eiiiuents from said iirst and said second reaction zones to produce a gas rich in hydrogen and carbon monoxide as a product of the process, passing reduced metal oxide from said irst re A i 19 v action zone to a third reaction zone, suspending reduced metal oxide in a stream of air in said third reaction zone under exothermic conditions and at a temperature above that maintained in both said rst and said second reaction zones such that reduced metal oxide is oxidized, and withdrawing. reoxidized metal oxide from said third reaction zone, and returning reoxidized metal oxide from said third reaction zone to said first reaction zone at a temperature above that maintained in said rst reaction zone to supply heat thereto.

17. A process for producing a gas rich in hydrogen and carbon monoxide which comprises introducing finely-divided iron oxide and coal into a. rst reaction zone, suspending iron oxide and coal in a gasiform fluid substantially free from free oxygen such that a pseudo-liquid phase of finely-divided particles is formed in said first reaction zone, maintaining in said rst reaction zone a temperature between about 1300 and about l50F., a pressure between about 100 and about 650 pounds per square inch gage and a ratio by weight of iron oxide fed to the first reaction zone based'on coal fed to the first reaction zone of between about 4:1 and about 40:1 such that car-V bon is oxidized to carbon monoxide as the principal reaction by the reduction of iron oxide, said iron oxide being the principal source of oxygen for the oxidation of coal to carbon monoxide, withdrawing reduced iron oxide from said first reaction zone, passing reduced iron oxide from said iirst reaction zone to a second reaction zone, suspending reduced iron oxide in said second reaction zone in a stream of steam such that a psuedo-liquid phase of finely-divided particles i's formed, maintaining in said second reaction zone a. temperature within 150 F. of the temperature of said first reaction zone such that reduced iron oxide is reoxidized by reaction with steam to produce hydrogen as the principal reaction, the combined reactions of said first and said second reaction zones being endothermic, combining effluents from said rst and said second reaction zones to produce a gas rich in hydrogenk and carbon monoxide as a product of the process, withdrawing reoxidized metal from saidfsecond reaction zone and returning same to said first reaction zone, passing reduced iron oxide from said iirst reaction zone to a third reaction zone, suspending reduced iron oxide in said third reaction zone in a stream of air such that a pseudo-` liquid phase of nely-divided particles is formed, maintaining said third reaction zone under exothermic conditions at a temperature at least 50' F. above the temperature of both said first and said second reaction zones lsuch that re-V tacting a finely-divided reduciblemetal oxide se# lected from at least one of the group consisting of the oxides of iron, cobalt, nickel, molybdenum, manganese, barium, vanadium, chromium and copper with a finely-divided solid carbon-con taining material in a reaction zone, suspending the mass of finely-divided reducible metal oxide and solid carbon-containing material in a gasiform fluid substantially free from free oxygen in said reaction zone, maintaining said reaction zone during contact between reducible metal oxide and carbon-containing material under endothermic conditions and at a temperature such that car'- bon is oxidized to carbon monoxide as the principal reaction by reduction of said metal oxide, thereafter reoxidizing reduced metal oxide by contact with free oxygen under exothermic conditions at a higher temperature for reuse in the reaction in which carbon is oxidized to carbon monoxide and to supply heat thereto, and recovering from said reaction zone an eiiuent comprising carbon monoxide as a product of the process, said reducible metal oxide being the principal source of oxygen for the oxidation of carbon to carbon monoxide.

NORMAN L. DICKINSON.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Numbel` Name Date 1,969,264 Grant Aug. 7, '1934 2,400,075 Claussan May 14, 1946 2,449,635 Barr Sept. 21, 1948 2,507,502 Corner et al May 16, 1950 FOREIGN PATENTS Number Country Date 7,518 Great Britain Y July 29, 1887 8,239 Great Britain Mar. 10, 1900 OTHER REFERENCES Hongen et al., Chemical Process Principles, part one, pages 254-255, 26S-267. 

11. A CONTINUOUS PROCESS FOR PRODUCING A GAS RICH IN HYDROGEN AND CARBON MONOXIDE WHICH COMPRISES PASSING A GASIFORM FLUID SUBSTANTIALLY FREE FROM FREE OXYGEN UPWARDLY IN A FIRST REACTION ZONE THROUGH A MASS COMPRISING FINELY-DIVIDED REDUCIBLE METAL OXIDE AND COAL AT A VELOCITY SUFFICIENT TO MAINTAIN SAID MASS IN A PSEUDO-LIQUID FLUIDIZED CONDITION, MAINTAINING SAID FIRST REACTION ZONE AT A TEMPERATURE SUCH THAT CARBON IS OXIDIZED TO CARBON MONOXIDE AS THE PRINCIPAL REACTION BY THE REDUCTION OF SAID METAL OXIDE, SAID REDUCIBLE METAL OXIDE BEING THE PRINCIPAL SOURCE OF OXYGEN FOR THE OXIDATION OF SAID CARBON TO CARBON MONOXIDE, SEPARATELY WITHDRAWING FROM SAID FIRST REACTION ZONE FINELY-DIVIDED REDUCED METAL OXIDE AND AN EFFLUENT COMPRISING CARBON MONOXIDE, PASSING A PORTION OF SAID WITHDRAWN REDUCED METAL OXIDE TO A SECOND REACTION ZONE, PASSING STEAM UPWARDLY IN SAID SECOND REACTION ZONE THROUGH A MASS COMPRISING FINELY-DIVIDED REDUCED METAL OXIDE AT A VELOCITY SUFFICIENT TO MAINTAIN SAID MASS IN A PSEUDO-LIQUID FLUIDIZED CONDITION, MAINTAINING SAID SECOND REACTION ZONE AT A TEMPERATURE SUCH THAT SAID REDUCED METAL OXIDE IS REOXIDIZED BY REACTION WITH STEAM TO PRODUCE HYDROGEN AS THE PRINCIPAL REACTION, THE COMBINED REACTIONS OF SAID FIRST AND SAID SECOND REACTION ZONES BEING ENDOTHERMIC, SEPARATELY WITHDRAWING FROM SAID SECOND REACTION ZONE FINELY-DIVIDED REOXIDIZED METAL OXIDE AND AN EFFLUENT COMPRISNG HYDROGEN, COMBINING THE EFFLUENT FROM SAID FIRST REACTION ZONE WITH THE EFFLUENT FROM SAID SECOND REACTION ZONE TO FORM A GASEOUS MIXTURE COMPRISING HYDROGEN AND CARBON MONOXIDE AS THE PRODUCT OF THE PROCESS, PASSING ANOTHER PORTION OF SAID REDUCED METAL OXIDE FROM SAID FIRST REACTION ZONE TO A THIRD REACTION ZONE, PASSING AIR UPWARDLY IN SAID THIRD REACTION ZONE THROUGH A MASS COMPRISING FINELY-DIVIDED REDUCED METAL OXIDE AT A VELOCITY SUFFICIENT TO MAINTAIN SAID MASS IN A PSEUDO-LIQUID FLUIDIZED CONDITION WHEREBY SAID REDUCED METAL OXIDE IS REOXIDIZED AT A TEMPERATURE ABOE THAT MAINTAINED IN BOTH OF SAID FIRST AND SAID SECOND REACTION ZONES AND HEAT IS LIBERATED, AND WITHDRAWING REOXIDIZED METAL OXIDE AT A RELATIVELY HIGH TEMPERATURE FROM SAID THIRD REACTION ZONE AND PASSING SAME TO SAID FIRST REACTION ZONE AT A TEMPERATURE ABOVE THE TEMPERATURE LEVEL MAINTAINED THEREIN AS MEANS FOR SUPPLYING HEAT OF REACTION THERETO.
 12. THE PROCESS OF CLAIM 11 IN WHICH SAID GASEOUS MIXTURE OF HYDROGEN AND CARBON MONOXIDE IS PASSED TO A FOURTH REACTION ZONE IN WHICH HYDROGEN AND CARBON MONOXIDE ARE CONVERTED TO ORGANIC COMPOUNDS INCLUDING METHANE, REMOVING AN EFFLUENT FROM SAID FOURTH REACTION ZONE COMPRISING UNREACTED HYDROGEN, METHANE AND HIGHER BOILING ORGANIC COMPOUNDS, SEPARATING UNREACTED HYDROGEN AND METHANE FROM SAID EFFLUENT, AND PASSING SAID UNREACTED HYDROGEN AND METHANE TO SAID FIRST REACTION ZONE AS AT LEAST A PORTION OF THE GASIFORM FLUID. 